


Seafoam

by Anonymous



Category: Dororo (Anime 2019)
Genre: Alternate Universe - Creatures & Monsters, Alternate Universe - Merpeople, Alternate Universe - Pirate, Ambiguous/Open Ending, Attempted Seduction, Complete, Heavy Petting, Human/Monster Romance, Lust, Lust at First Sight, M/M, Moral Ambiguity, Mythical Beings & Creatures, Not Beta Read, Other, Other Additional Tags to Be Added, Porn With Plot, Porn with Feelings, Prince Tahomaru, Sex, Siren Hyakkimaru, Sirens, Slight feelings?, Spells & Enchantments, They're not siblings I suppose here, Touching
Language: English
Status: Completed
Published: 2019-07-13
Updated: 2019-07-14
Packaged: 2020-06-27 07:39:10
Rating: Explicit
Warnings: Graphic Depictions Of Violence, Underage
Chapters: 2
Words: 4,116
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/19786300
Author URL: https://archiveofourown.org/
Summary: The lulling notes echoed across the rolling waves once again. A soft voice, androgynous and ambiguous, to curl around every word and syllable and to call another foolish man into the sea’s cold maw, never to be seen again. Chilling, uncomfortably beckoning, or...Prince Tahomaru vows to find and capture the allusive creature luring his men into the sea.





	1. Capture

**Author's Note:**

> This is an AU I thought up that I very much wanted to expand upon.  
> I hope you like it as I do.

_ “ _ _ Pick a red flower to give to her, I’ll place the flower, Red flower, red flower, in her hair,”  _

_ The lulling notes echoed across the rolling waves once again. A soft voice, androgynous and ambiguous, to curl around every word and syllable and to call another foolish man into the sea’s cold maw, never to be seen again. Chilling, uncomfortably beckoning, or... _

“Haunting,” that was the word Tahomaru searched for as he raised his arm, signaling to his crew to insert small plugs into their ears. 

“Quite, sir. I haven’t seen any of ours jump ship just yet.” Mutsu, the esteemed navigator and Tahomaru’s trusted childhood friend commented, enunciating more than usual as to speak over the simple plugs. 

“Excellent thinking of the makeshift earplugs.” She glanced to her side towards her young captain and prince. 

“No time for celebrating just yet. We still have to catch the damn snake.” Tahomaru let out a sigh and surveyed his men from the highest tier of his ships’ deck. His men lined the sides of the ship, looking out over the dark evening waters. They brandished various different weapons, all alert and in ready stances. 

‘How had it come to this,’ Tahomaru thought bitterly as he folded his arms over his chest. He looked almost glamorous next to his simply dressed crew members. Rich red silks and golden fabric adorning him, a large red feather perched in his cap, ornate sword held fast against his belt. Surely a worthy captain to dictate his crew with a firm word and guiding hand. 

The hunt had began a or so week prior. The hunt for the serpents lurking beneath the ocean who had claimed another three of his men in as little as a week. It had to be a pack of them, surely. No lone beast would dare to disturb the kingdom of Daigo and their citizens repeatedly without a death wish. Or excessive hubris. 

The ship, given the title ‘Ishikawa’, had sailed peacefully for most of her maiden voyage to survey the seas surrounding the bountiful kingdom. 

Only recently, as she sailed into more uncharted and vaguely written of waters, did the lulling begin. 

First, it was pleasant music from seemingly nowhere. It confused and fascinated many a sailor who wandered the decks at night, or so Tahomaru had gathered. Then the voices followed. Luring words or bits of melody, sounding to be either a beautiful feminine call and a gentle masculine urgency from just over the ships deck. When the first man went overboard, it had been assumed a tragic accident. They mourned, briefly. 

Then within a day, another man jumped ship. Lunacy, they had chalked it up to. Then within two more days, a man in clear view jumped ship right before some crew men's eyes. A song, a duet of unearthly voices, cascaded and permeated through the air and was too much to ignore. A state of uncontrollable longing overtook half the crew and beckoned them to the sea. Some needed to be restrained by the unaffected before they hurled themselves over the side of the ship as well. 

When all was said and done, it was no longer such an accident. 

“They were so beautiful,” a crewmen had told his captain with awe and fear all mixed together in his weary expression. 

“We couldn’t stop them, the weak ones, my lord. They just.. Jumped.” 

Tahomaru wouldn’t stand for it any longer. He would do all in his power to protect his men and to assure no other ship would be lured into such a fate. It would be his father’s wish, undoubtedly, that he vanquish or capture these sea demons and restore the peace. Recovering such a creature would prove to be quite the prize for the kingdom. 

All they had to go off of were mere glimpses of dark hair, scales, and a flurry of movement underneath the water. 

But with a fine tuned plan and a hunch, Tahomaru had more than he needed. 

_ “It will bloom and sway like the sun, Pick a white flower to give to her,” A lone masculine voice sang, the voice echoing about the air and seeming to fill the space. Sofficating and hypnotic. It was beautiful, though the men aboard knew better.  _

“Hyogo, any word?” Tahomaru turned to his other side, eyeing his first mate verily as he returned from the lower deck. 

“None, sir. Though the song seems to be getting uh.. Louder as no one goes over.” The built man responded and seemed pensive. 

“I gamble the harder we resist, the more the beast will stir.” Mutsu nodded her head towards her brother and back to their prince. 

Tahomaru put his hand to his chin in thought. 

“... we wait. It surely does not understand that we can’t be affected with these,” He gestured to the plugs in their ears. 

A few yells came from the side of the ship and multiple men crowded around the railing. 

"Captain! Come quick! It's a whole swarm of sea hags!" Someone yelled and the sound of splashing came through, despite their ears being covered. 

Tahomaru broke into a sprint, down the deck and watched in horror as he watched a crew mate shove away from the others holding him back as he dove over the rail and into the dark water below. 

He shoved his way through the crowd that formed in time to see a horrifying, but intriguing scene.

What appeared to be a woman, though distinctly foreign with red fins protruding from the sides of her head through thick brown locks, biting into the neck of the enamored sailor in her arms. She looked to be shushing him, letting the blood leave his flesh and into the surrounding surf. She tore a chunk of flesh from the man as she reeled back. Her lips were bright red with her kill, yet despite the blood gushing down her face, she was so beautiful. 

She glanced behind her, waving her hand as a group of smaller, almost childlike sea creatures came up from the water and surrounded the fresh corpse in the woman's arms. She smiled kindly to them, seeming to urge them to come closer. 

With haste, one of the children with their brown hair tied up in a short ponytail and oversize green fins, grinned widely at the older woman before grabbing the corpse of the man and diving under the waves again. The others quickly followed. 

The scene was stupefying. The men lined along the deck frozen in either awe, fear, or trance.

Though what truly caught the Prince's gaze was the sight of a gorgeous, almost ghostly figure perched atop some rocks, lips parted in song and eyes dark and alluring. Long dark hair trailed down the sirens’ bare chest and back, stark in comparison to his pale skin. An enormous dark blue tail swayed at his bottom half, some fins looking to be torn and lace-like. Silver scales lined down his hips and waist, sparkling in the moonlight. 

  
  
  


A few crew mates leaned over the railing, looking desperate to get closer to the beautiful voices and the doll-like features of the creatures. Some pulled their earplugs free and threw them aside before throwing themselves to the sea. 

Tahomaru was frozen. His eyes widened, grip tightening on the rail of the Ishikawa. His hands trembled, his heart rate picked up. His lips felt dry. He wished they were wetter. Maybe they’d feel better pressed to the soft skin of that strange man- 

Tahomaru slammed his hands down onto the railing and turned fast, grabbing the harpoon Hyogo held in his own trembling hands. He looked in a similar state of enticement and trance, as did Mutsu at his side. The earplugs meant nothing when within the sight of the siren himself. 

It had dawned on him. 

_ That  _ was the source. 

With all the might he could muster against his bubbling desire, he threw the harpoon.

It all happened too quickly. 

The spellbinding song stopped abruptly, a shout of pain breaking from the man’s lips as the harpoon embedded in his hip. A dark blue liquid gushed from the wound. He looked too shocked to even make a sound. 

“Hyakkimaru!”

  
The woman siren cried and started to swim fast towards the rocks as the green finned child broke back to the surface with a terrified expression.

Tahomaru felt like stones were lifted from his chest as the song was halted. He looked to the rope fastened firmly to the harpoon in the creature and grabbed to it quickly. He pulled hard, a demystified Mutsu and Hyogo joining their captain in pulling.    


“Heave!” He shouted.

The male siren held his hand out to his friend, his eyes flashed to the deck of the boat, urgently surveying the situation. He looked back to the woman and shook his head urgently even as pain tore at his side as he was suddenly tugged towards the ship.    


“Go! Protect!” he said firmly and pointed behind the woman to the multiple children merpeople who peeked up from the waves. 

“Aniki, no!” One child shouted, sloppily swimming forward but getting tugged back by the woman who held their arms tightly. She had tears dripping down her scaled cheeks. 

The man hissed in pain, sharp teeth bared as he was pulled from the rocks and into the water in the direction of the ship. He looked to the woman and his expression read sullen urgency. 

The brown haired woman nodded her head bitterly and with one last glance to the human ship, she turned to the children, arms still firmly around one squirming child and dove back under the waves and out of sight in the mix of seawater and blood. 

Tahomaru leaned over the side of the ship, entrusting the rope to his most capable men as they pulled the sea creature closer and up towards them. He reached over until he could grasp onto the surprisingly silky hair of the siren and yanked hard. He drew another alarmed hiss from the beast and dragged him, albeit roughly onto the deck of the ship. 

Tahomaru threw the creature down with a huff and leaned over him, pressing his hand firmly to their humanoid mouth. He looked the siren square in the eyes.   
  
“Welcome aboard, serpent.” He said coolly, frustration in the back of his mind. Anger for his slaughtered men and pride for his catch. The prince looked down at him, into his dark animalistic eyes with his own strong demeanor. 

“You’re our prey now.” 


	2. Release

**Notes for the Chapter:**

> The continuation and closing. 
> 
> Hardcore unbeta'd it's 1am

_ Blood stained his clawed hands as he gazed at them, drawing his trembling fingers away from the terrible protrusion of the harpoon in his side.  _

_ 'No… no, what-' The thought barely had time to cross his mind before the first yank came. It sent him tumbling gracelessly into the surf underneath the rocks and for a moment, he felt breathless, his gills useless to him.  _

_ Hyakkimaru felt a bubbling hiss of pain leave his mouth as he was heaved toward the imposing ship before him.  _

_ He heard the panicked cry of his hunting partner, Mio and already knew it was too late for himself.  _

_ But not for his family.  _

_ "Go! Protect!" He pointed urgently to the children rising and breaking the surface behind his panicked companion.  _

_ He held back another grunt of agony as the harpoon tore into his scales and flesh, coloring the water with blueish blood.  _

_ Hyakkimaru cursed himself under his breath as he watched his closest sibling break from the waves and start towards him in a panic. He thanked the sea that Mio caught them.  _

_ He pointed urgently the two to move away and shot his gaze to the vessel that pulled him in.  _

_ His heart felt as if it stopped as they swam away, either in relief his family would live another day or fear of his inevitable death, he couldn't say.  _

  
  


They had thrown him in some dark, dank room below deck. 

They had attached him to the wall, a metal chain fastened around his neck and held taunt to not provide him room to move very far. It burned against his throat with every breath, his gills useless in the air. 

He grunted in discomfort, shifting to lay on his uninjured side against the creaky floorboards. 

The man who had dragged him by the hair up onto the deck of the ship had insisted to some of his men that his wound be at least wrapped. Which surprised the merman greatly. He assumed he would be killed on the spot, throat slit and head mounted on the front of their ship as an example, as many sirens before him who were taken by men were. 

A woman, ordered by the man who captured him, cleaned his wound. She had a large man hold his wrists in a vice grip above his head, unmoving as he hissed and struggled. It did little good above water. 

They had shoved a cloth into his mouth and tied it around his head to silence his voice. He felt woozy and uncomfortable. The crew men around the deck looked at him with a mixture of anger, disgust, or visible lust. 

When the woman finished stopping the bleeding and wrapped a dirty bandage around his waist, her and the man had looked to the same man who had talked so angrily to him as he was pulled on board. 

_ “You’re our prey now,”  _ The man had practically growled into his face. He was well dressed, carried himself with esteem and pride. Dark hair and resolve in a simple glance. That he could tell just for an instant. 

Hyakkimaru could only assume he was the vessel's leader.

“Throw it below deck in the brig. Father will want to see it to decide punishment for the slaughter of daigo’s citizens,” The man, a young one from what Hyakkimaru could tell, ordered before casting a glance in his direction. 

“or if it’s even worth keeping alive.” 

The man waved his hand dismissively, and off he was thrown into the small room. 

He already felt exhausted, blood loss and disorientation clouding his thoughts on the whole situation. Simply put, he was captured. 

‘At least everyone is safe,’ He thought tiredly, rubbing at his face and feeling the slight dryness of the scales dotting his cheeks. 

There was a faint click. 

Hyakkimaru looked up slowly, his large brown eyes locked onto the figure standing in the doorway. 

The ornately dressed young man. 

He looked at him with an unreadable expression. Possibly appraising. 

The captain stepped forward further into the prison, his boots clicking against the floor as he made long, drawn out strides. He knelt before his captive and squinted. 

Hyakkimaru felt his blood run cold. 

  
  


-

  
Tahomaru cleared his throat as he examined the creature.    
  
Of course, it appeared humanoid enough. Beautiful, in some respects with it’s long brown hair falling in cascades down it’s chest and back. It’s wide, alluring eyes and plush pink lips. The image of inhuman grace. Like angels in legend. 

Tahomaru knew better but still. He was fascinated. 

“... A man eater. I always knew your kind was lurking, though I didn’t realize so closely to shore,” He commented, sighing quietly to no one in particular. He tilted his head as he met the merman’s gaze. 

“Can you understand me, serpent?” 

The merman made a face, nose wrinkling and a crease appearing between it’s delicate brows. 

Tahomaru couldn’t help the slight laugh that came from himself, at the realization the creature could, in fact, understand him. He supposed it didn’t take too kindly to the term of endearment. 

“... So I suppose you can,” He rolled his eyes. 

The creature stared back at him with a blank expression. Unreadable. 

Exhausted. 

Tahomaru drew his eyes away. 

He shouldn’t look upon the creature with anything other then indifference or distain. Yet here he was, eye level with the thing and feeling pity. 

His eyes skimmed down and lingered about the length of the siren’s long tail. Dark navy scales and lace grey fins. There were faded scars and silver scales littering through the blues. The prince couldn’t help but marvel. 

Tahomaru slowly reached out, holding his palm just over the scales but stopped when the creature twitched and moved against the wall where it was chained. It’s eyes were blown wide and the fins protruding from their scalp flared in visible fear. 

He should leave. He should wait until his father inevitably orders the siren’s death. 

He should. But he didn’t. 

“I’m not going to hurt you,” Tahomaru raised his hand up in a sign of disarmament before slowly moving to lower his palm again. The chance was too rare. He touched the scales delicately and marveled in their smooth texture and the coolness of the appendage. 

The creature’s nostrils flared and it made a faint noise around the cloth in it’s mouth. It sat up to the fullest of his ability, gagging as the chain around its neck pulled tight again. 

Tahomaru watched with faint interest, catching the wild-eyed look in the creature’s gaze. He swallowed thickly.    
  
He shouldn’t. He definitely shouldn’t. 

He trailed his fingertips up along the glistening scales to feel up the siren’s slim hips and waist in a smooth motion, careful not to press on or disturb the newly given and dressed wound. 

Hyakkimaru shivers under the human’s warm hands and soft touches, both very foreign to him. He feels a noise build deep in his throat, a gut reaction to the slow pressure on his tail. A soft hum and almost like a purr. 

He’d never felt warmth that traveled to his core in such a way. It frightened him.

Tahomaru breathed out shakily as he trailed his hands up and down his scales with curiosity. He thought he couldn’t be anymore curious or amazed. Not before feeling something strange. 

He blinked. 

Running his hand slowly but with more firmness against just under the siren’s waist where human-like flesh met scales, his fingers delved just slightly into a lightly wet opening. 

Hyakkimaru gasped faintly around the gag, saliva and water mixing together in his mouth on the cloth and his body shivering. 

Tahomaru couldn’t tear his eyes away from the bizarre opening his fingers pressed over before swallowing thickly once again. 

“.. I’m not sure why I’m doing this,” He mumbled under his breath before pressing one finger shallowly into the warm, wet heat of the Siren’s body. 

The reaction is instantaneous. Hyakkimaru’s back arches and his clawed fingers reach out, grasping at Tahomaru’s leg and digging in, not in malice but for dear life. A muffled moan breaks from his lips. 

Tahomaru swirls his finger into the tight, wet heat and his finger draws lightly against the tip of a protrusion, deep inside. He hums in fascination, brows up in surprise. 

“... So you’re a man,” he breaths out. 

“I couldn’t tell before..” he muses quietly to the merman. He doesn’t even seem alarmed at the clawed fingertips squeezing against his calf through his slacks. 

“Creatures of the deep must be built differently than my kind,” 

Hyakkimaru makes another low noise and simply nods, pupils blown wide and breathing a bit hurrided. His tail twitches, a wince following from the chains on his throat. 

Tahomaru takes a deep breath in and out as he trails his eyes over the gorgeous man before him. He feels foolish, but for once he shall indulge. After all, the man seems pleased as well. 

Withdrawing his fingers from the creature’s slit, he fiddles quickly with his slacks and frees his now aching cock from it’s confines. It had been a while since the young prince had anyone, be it man or beast, these days. 

He stroked himself once, twice and looked to the siren’s gaze, holding it for a long moment. 

He reached out slowly, cupping the siren’s cheek with his palm. He softly tucked a stray lock of hair behind the merman’s ear, almost tenderly. 

Tahomaru’s mouth felt unbearably dry. His mind drew through all the thoughts of how wrong and idiotic he was being, but under a spell or not, he was enraptured. 

He swallowed his pride. Or his last rational thought. 

“My name. If I must have you, you should know. My name is Tahomaru.” He said with finality before climbing practically onto the merman’s lap and lining his hard cock up with his wet opening. 

Hyakkimaru stared back at him, his own mind clouded and hazy from the onslaught of pleasant strokes and prodding. A human man treating a beast with such care. It made his chest feel tight and a warm buzz to fill his nerves. 

He still could not respond but he felt himself nod anyway. 

Tahomaru braced Hyakkimaru’s shoulder before sinking into his wet heat and a gasp left his lips as he bottom out into him, feeling his own cock rub alongside the appendage buried deep inside the other. 

Hyakkimaru squeezed his eyes shut, his own hands coming to hold to Tahomaru’s waist and firmly press him into himself. It felt too funny and strange to let slip by. He wanted to feel more. 

Tahomaru set a quick rhythm, rocking himself over the siren and slamming over and over into his soaked body. His own hands found his partners waist and chest, caressing and scratching lightly at the flesh and scales littering his sides. 

He was so tight, squeezing the prince’s cock perfectly as he fucked into him desperately for release. He chased his pleasure selfishly, as young princes are wont to do. 

When he came, Tahomaru swore he felt bliss, his cock milked for all his worth into the welcoming wetness of the siren underneath him, yet practically embracing him. 

Hyakkimaru’s cries were muffled behind his gag and tears pricked at the corners of his eyes as he came alongside Tahomaru. He shook and trembled with ecstasy. 

  
  


Breathing heavily, Tahomaru sat up slowly, pulling his spent cock from the lovely man and putting himself back into his trousers with little fanfare. His gaze drifted over the siren who was leaned back against the wall, eyes clouded with heat and flesh flushed from exertion. 

The prince felt a pang of sadness flow through him. He was being stupid, he knew. But gods, how he found himself starstruck. 

Tahomaru cursed his heart quietly as he found himself reaching forward to the lock holding the chain to the captive’s neck and rummaged in his pocket, producing a key and slipping it into the lock. He let the chain clink to the floor. 

Next he brought his hands to the siren’s view before moving them carefully to the back of his head and undoing the tightly done gag after a few tries. He pulled it away gracelessly and threw it aside.

“... Let’s get you out of here.” He grunted as he came to his knees, suddenly lifting the still blissed out merman into his arms and rising to his feet. 

  
Maybe he was an idiot, maybe he was easily fooled, Tahomaru couldn’t say. But he felt something for the strange siren, be it his beauty or his song. He was drawn. 

After checking the coast was clear, Tahomaru came to the deck of the ship, the full moon shining brightly overhead. 

By now, the merman in his arms was looking at him skeptically, his senses having to have returned to him though he hadn’t uttered a word as the man snuck about the ship with the merman in tow. 

Arriving to the side of the boat, Tahomaru took a heavy breath. 

“I’m not sure whether you’ve got me under a spell or I’m just plain stupid,” He commented and looked into the merman’s face. 

A soft laugh left those pretty lips, a small fanged smile visible on Hyakkimaru's mouth. 

He merely shook his head. 

“No spell.” he said simply and his eyes read coyness that made Tahomaru’s cheeks burn. Did this creature just call him stupid? 

“Tahomaru,” The merman looked at him rather seriously, sitting up a bit in his grip and touching his cheek. 

Tahomaru was surprised when he lightly pressed their foreheads together and gave him a light nuzzle. 

“My name… is Hyakkimaru.” The siren said quietly, like he was trying to make sure he spoke correctly. 

Tahomaru’s breath hitched. 

“Hyakkimaru…” he breathed and stepped closer to the side of the ship. He looked down at the dark water lapping against the wood. 

“Will we see each other again?”    
  
Hyakkimaru tilted his head slightly, almost in thought before he nodded curtly.    
  
“We will. Someday.” 

With a sudden push, the siren broke from the prince’s grasp.

And was gone beneath the waves. 

**Notes for the Chapter:**

> Feedback appreciated!!!

**Author's Note:**

> Next chapter, the rating will go up and more explicit Taho/Hyakki will take place. 
> 
> Feedback appreciated and very much enjoyed.


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